Author: Sandro Tosi
Last modified: 2005-09-20
Linux kernel set itself up at boot-time gathering information from the
hardware on which it's running.
BogoMIPS are a metric unit used to synchronize scheduler and internal
kernel timers. They have no real value but they are just a value to
setup the kernel. They are named BogoMIPS, not PIPS...
Do not use BogoMIPS as a performance value: you cannot compare
different processors or architecture with them. They depends on
processor frequency, for the same architecture. On recent popular
CPUs, BogoMIPS are approximately twice the megahertz of the CPU, but
this may vary a lot.
In and SMP environment (Symmetrical MultiProcessor) only the first
processor contributes to setup kernel, but BogoMIPS are calculated
even for the second one and a total from the machine is computed, as
from this /var/log/kern.log extract:
kernel: Detected 867.646 MHz processor.
kernel: Calibrating delay loop... 1716.22 BogoMIPS (lpj=858112)
kernel: Calibrating delay loop... 1728.51 BogoMIPS (lpj=864256)
kernel: Total of 2 processors activated (3444.73 BogoMIPS).
Wim van Dorst has written a detailed ``BogoMIPS mini-Howto'',
available at http://www.hobby.nl/~clifton/bogomips.html